PENICILLIUM. 



Observe Penicillium growing upon bread in a moist 

 aim osphere. * Note : 



I. General Characters. 



Velvety-looking surface, white in young 

 specimens, dull bluish green in older 

 stages. 



Touch a mass of Penicillium spores ivith a needle- 

 point, and dip the needle-point into a drop 

 of water upon a slide. Cover, and examine 

 with a low and then ivith a high power. 

 Note : 



Size. (Measure.) 

 Form. 



In the same way sow some spores in Pasteur's 

 fluid in a watch-glass. Put the watch-glass into 

 a moist chamber. With a hand -lens watch 

 the development of the mycelium from day to 

 day. 



II. Structure. 



Examine germinating spores (sown twenty-four 

 hours previously in a vessel of Pasteur's fluid). 



Observe and sketch a series of stages in the germina- 

 tion of the spores, noting : 



* To obtain Penicillium, keep a cut lemon for a few days in a 

 moist atmosphere. 



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